Syringe with retractable needle

Abstract

The invention discloses a syringe construction which permits use of standard hypodermic needles and allows the hypodermic needle to be retracted into the body of the syringe after use to minimize accidental pricking from the needle by withdrawing the needle into the syringe body such that it is not exposed. The invention provides for a syringe body having an engaging thread on the distal end for receiving a hypodermic needle, adjacent to the engaging thread is a positioning groove and locking surfaces for engaging a needle carrier, a needle carrier is removably engaged to the body which has a distal end which will mate with the needle and a proximal end providing an engaging means for engaging the syringe plunger. The plunger has a engaging means for engaging the needle carrier such that the needle carrier can be rotated and retracted into the syringe body.

We claim: 
     
       1. A syringe apparatus comprising: (a) a wall defining a syringe body having a passageway therethrough having a distal end and a proximal end;   (b) a needle engaging means positioned at the distal end for attaching a needle to the syringe body;   (c) a carrier engaging means on said syringe body adjacent to said needle engaging means for holding a retractable needle carrier, said needle engaging means and said carrier engaging means rotatably engage the needle and needle carrier in opposite directions of rotation;   (d) a needle carrier retractably engaging said carrier engaging means comprising: (i) a carrier wall defining a passageway therethrough having a distal end and a proximal end;   (ii) syringe body engaging means on the outer wall of said needle carrier for engaging the carrier engaging means of said syringe body;   (iii) plunger engaging means located at the proximal end of said needle carrier for engaging a plunger such that the needle carrier means may be retracted into the syringe body upon manipulation of the plunger;   (iv) needle engaging surface on the distal end of said needle carrier for engaging the needle.     
     
     
       2. The apparatus of claim 1 further comprising: (a) a plunger body having a distal end and a proximal end and of sufficient length that a portion of the body will extend beyond the proximal end of said syringe body when said plunger body is pushed completely into the syringe body;   (b) a carrier engaging means for engaging the carrier engaging means to allow retraction of the needle carrier means into the said syringe body and located at the distal end of the plunger body;   (c) a sealing means located adjacent to the carrier engaging means for providing a slidable seal with the interior wall of said syringe body; and   (d) a surface located at the proximal end of said plunger body which permits manipulation of the plunger body.   
     
     
       3. A syringe apparatus comprising: (a) a wall defining a syringe body having a passageway therethrough having a distal end and a proximal end;   (b) a needle engaging means positioned at the distal end of said syringe body for positioning a needle on the syringe body;   (c) a carrier engaging means on said syringe body for holding a retractable needle carrier;   (d) a needle carrier means retractably engaging said carrier engaging means comprising: (i) a carrier wall defining a passageway therethrough having a distal end and a proximal end;   (ii) a syringe body engaging means on the outer wall of said needle carrier means for engaging the carrier engaging means of said syringe body;   (iii) a needle engaging surface on the distal end of said needle carrier;   (iv) a needle carrier sealing means located adjacent to said syringe body engaging means for assurance of a liquid-tight seal between said needle carrier means and said syringe body when said needle carrier is fully mated with said syringe body;   (v) the distal end of said needle carrier being dimensioned to frictionally engage a needle;   (vi) a plunger engaging means formed by a plurality of splines at the proximal end of said needle carrier for engaging a plunger to permit retraction of said needle carrier into said syringe body.     (e) a plunger comprising: (i) a plunger body having a distal end and a proximal end, said plunger body of sufficient length such that a portion of said plunger body will extend beyond the proximal end of said syringe body when said plunger body is pushed completely into said syringe body;   (ii) a needle carrier engaging means formed by a plurality of splines located on the distal end of said plunger body for engaging said needle carrier means to allow for retraction of said needle carrier means into said syringe body;   (iii) a seal which slidably engages the inner wall of said syringe body, said seal located adjacent to said needle carrier engaging means and providing a slidable seal with the interior wall of said syringe body; and   (iv) a proximal end having a surface which permits manipulation of said plunger body.     
     
     
       4. The apparatus of claim 3 wherein said needle engaging means positioned at the distal end of said syringe body for positioning a needle to said syringe body is a thread surface located on the inner wall of said syringe body. 
     
     
       5. The apparatus of claim 3 wherein said carrier engaging means on said syringe body is comprised of positioning grooves located on the interior wall of said syringe body. 
     
     
       6. The apparatus of claim 3 wherein said syringe body engaging means of needle carrier comprises engaging lugs which mate with and rotate relative to said positioning grooves means to provide retractable engagement of said needle carrier means to said syringe body. 
     
     
       7. The apparatus of claim 3 wherein the splines of said plunger engaging means are formed on the proximal end of the interior of said needle carrier wall and said splines of said carrier engaging means of the plunger are formed on the outer portion of the distal end of said plunger body. 
     
     
       8. The apparatus of claim 7 wherein each spline of said plunger engaging means has a camming surface located at the proximal end and having a pitch suitable to provide for orientation of said needle carrier engaging means located on the distal end of said plunger body such that the splines of said plunger body mates with and slidably engages said needle carrier means. 
     
     
       9. The apparatus of claim 3 wherein the needle carrier engaging means further comprises a mating surface means for interaction with said plunger engaging means located on the proximal end of said needle carrier. 
     
     
       10. A syringe apparatus comprising: (a) a wall defining a syringe body having a passageway therethrough having a distal end and a proximal end;   (b) a thread surface positioned at the distal end for attaching a standard hypodermic needle to the syringe body;   (c) a carrier engaging means on said syringe body adjacent to said thread surface for holding a retractable needle carrier;   (d) a needle carrier retractably engaging said carrier engaging means comprising: (i) a carrier wall defining a passageway therethrough having a distal end and a proximal end;   (ii) syringe body engaging means on the outer wall of said needle carrier for engaging the carrier engaging means of said syringe body;   (iii) a plunger means to provide slidable frictional engagement located at a proximal end of said needle carrier for engaging a plunger such that the needle carrier means may be retracted into the syringe body upon manipulation of the plunger; and   (iv) the distal end of said needle carrier dimensioned to engage a standard hypodermic needle.     
     
     
       11. The apparatus of claim 10 wherein said carrier engaging means is a positioning groove located on the interior of said wall body. 
     
     
       12. A syringe apparatus comprising: (a) a wall defining a syringe body having a passageway therethrough having a distal end and a proximal end;   (b) a needle engaging means positioned at the distal end of said syringe body for rotatably positioning a needle on the syringe body;   (c) a carrier engaging means on said syringe body for rotatably holding a retractable needle carrier, said needle engaging means and said carrier engaging means rotatably engage the needle and needle carrier in opposite directions;   (d) a needle carrier means retractably engaging said carrier engaging means comprising: (i) a carrier wall defining a passageway therethrough having a distal end and a proximal end;   (ii) a syringe body engaging means on the outer wall of said needle carrier means for engaging the carrier engaging means of said syringe body;   (iii) a needle carrier sealing means located adjacent to said syringe body engaging means for assurance of a liquid-tight seal between said needle carrier means and said syringe body when said needle carrier is fully mated with said syringe body;   (iv) the distal end of said needle carrier being dimensioned to functionally engage a needle;   (v) a plunger engaging means at the proximal end of said needle carrier for engaging a plunger to permit retraction of said needle carrier into said syringe body.     (e) a plunger comprising: (i) a plunger body having a distal end and a proximal end, said plunger body of sufficient length such that a portion of said plunger body will extend beyond the proximal end of said syringe body when said plunger body is pushed completely into said syringe body;   (ii) a needle carrier engaging means located on the distal end of said plunger body for engaging said needle carrier means to allow for retraction of said needle carrier means into said syringe body;   (iii) a seal which slidably engages the inner wall of said syringe body, said seal located adjacent to said needle carrier engaging means and providing a slidable seal with the interior wall of said syringe body; and   (iv) a proximal end having a surface which permits manipulation of said plunger body.     
     
     
       13. The apparatus of claim 12 wherein plunger engaging means located at the proximal end of said needle carrier means for engaging with said plunger body and the needle carrier engaging means of the plunger are a plurality of splines. 
     
     
       14. A syringe apparatus comprising: (a) a syringe wall defining a syringe body having a passageway therethrough having a distal and proximal   (b) a thread surface positioned on the interior of said syringe wall and positioned at the distal end of said syringe body;   (c) positioning grooves located on the interior of said syringe wall for retractably engaging a needle carrier;   (d) a retractable needle carrier retractably engaged within said syringe body and retractably engaging said positioning grooves, said needle carrier comprising: (i) a carrier wall defining a passageway therethrough having a distal end and a proximal end;   (ii) positioning lugs located on the outer wall of said needle carrier for engaging the positioning grooves of said syringe body;   (iii) the outer distal surface of said carrier wall dimensioned such that it will frictionally engage a needle;   (iv) spline surfaces located on the interior of said needle carrier wall at the proximal end of said needle carrier body for slidably engaging mating spline surfaces on a plunger; and     (e) a plunger comprising: (i) a plunger body having a distal end and a proximal end and of sufficient length such that a portion of said plunger body will extend from the proximal end of said syringe body when said plunger is fully inserted into said syringe body;   (ii) splines located at the distal end of said syringe body dimensioned to mate with the splines of said needle carrier;   (iii) a seal located adjacent to said splines of the plunger for providing a slidable seal with the inner surface of said syringe wall; and   (iv) a surface at the proximal end of said plunger for manipulation of the plunger user.     
     
     
       15. The apparatus of claim 14 wherein said thread surface and said positioning grooves impart rotation in opposite directions.